Glacier responses to recent volcanic activity in Southern Chile

Author

Abstract/Review

Glaciers in Southern Chile (39–43 S) are characterized by frontal retreats and area losses in
response to the ongoing climatic changes at a timescale of decades. Superimposed on these
longer-term trends, volcanic activity is thought to impact glaciers in variable ways. Debris–ash
covered Glaciar Pichillancahue-Turbio only retreated slightly in recent decades in spite of
been located on Volc´an Villarrica which has experienced increased volcanic activity since
1977. In contrast, the negative long-term Volc´an Michinmahuida glacier area trend reversed
shortly before the beginning of the explosive eruption of nearby Volc´an Chait´en in May 2008,
when Glaciar Amarillo advanced and a lahar type of mudflow was observed. This advancing
process is analysed in connection to the nearby eruption, producing albedo changes at
Michinmahuida glaciers, as well as a possible enhanced basal melting from higher geothermal
flux. Deconvolution of glacier responses due to these processes is difficult and probably not
possible with available data. Much more work and data are required to determine the causes of
present glacier behaviour.